By the time you read this, the world will have been informed of the brand new '06 Z06 Corvette. As we go to press, much of the data about this tremendous car has been leaked and posted all over the Internet. Some of it is close to fact and some is just plain wrong. While we can't control that process, we can give you firsthand knowledge of what we were provided by Chevrolet at the Z06 Backgrounder, held near Detroit on November 9, 2004.
When we got the invitation to this gathering of magazine editors (and rabid press dogs) from all over the United States, yours truly couldn't wait to get to Detroit to see what Chevrolet had come up with for the new Z06. At the event, Chevrolet unveiled a new yellow Z06, the new LS7 427 engine, and the new C6-R race car. While we were not allowed to take photos, we were given a press kit, along with a strict embargo date of January 10, 2005 at 12:01 a.m.
We're waiting for Chevrolet to ship a new Z06 for us to road test, but for now we'll discuss what we know.
The Z06 Corvette comes from a long line of Corvette performance-oriented options almost from the day of the car's inception. While the '63 Z06 was a full-on racing option based on the split-window coupe, the '01 Z06 was a model all its own, resurrected in the fall of 2000 as a third body style for the '01 model year. The Z06 option offered 385 hp from the new LS6 engine versus the standard 350 hp of the LS1. The LS6 nomenclature recalled the mighty 425hp, 427ci, aluminum-head big-block option of 1971. Z06 exterior colors were limited to black and red. The '02 Z06 was again reworked and rated at 405 hp, which was achieved by removing two of the pre-catalytic converters in the exhaust system. Induction was improved and high-lift camshafts were installed, acting on a lightweight valve gear. The '03-'04 Z06 Corvette continued to improve, mostly with various suspension upgrades. In 2006, an all-new Corvette Z06 will debut that's faster and has more power than any previous GM production vehicle.
When the cover was pulled from the new Z06, it was evident it was a completely new and improved "animal." It has an unmistakable and aggressive appearance, with design cues that include a wide front fascia with a large, forward-facing grille opening, a splitter along the bottom, and "Gurney lips" along the sides to provide aerodynamic downforce. There is a cold airscoop in front of the hood that integrates an air-inlet system for the new LS7 engine. The trailing edge of the front wheel opening is radiused to achieve improved drag, but protects the body finish with a tough molding, with a large air extractor behind the wheel.
The Z06 continues to use a fixed-roof body style, which optimizes body rigidity and aerodynamics. Wider rear fenders with flares cover the massive rear tires, and a brake-cooling scoop in front of the wheels visually balances the fender extractor. Believe it or not, the car now carries a tall rear spoiler on the rear fascia, housing the CHMSL. The Z06 also carries specific 10-spoke wheels, four larger stainless steel exhaust outlets, and new-design Z06 badging on the front fenders.
"The Z06 has been sculpted very carefully, with every element in its design serving a performance function. It also has a purposeful, menacing resemblance to the C6-R," said Dave Hill, Corvette's chief engineer.
The aerodynamics of the Z06's exterior were literally shaped by the experiences of the Corvette racing program, where high-speed stability and cornering capability are paramount. And while the race cars use large rear wings, the Z06's elevated spoiler provides sufficient downforce to balance the roadworthy front splitter without adversely affecting aerodynamic drag. The Z06's Cd is .31.
The Z06, since 2001, has sparked the second half of the C5's lifespan with a Corvette model for the extreme performance enthusiast. Now, Team Corvette combines the numerous attributes of the sixth-generation Corvette with the technology and winning determination from the C5-R program to take the new Z06 to the next level in total performance.
The links between racing and the production Z06 are both direct and indirect, as the vehicle was developed in conjunction with the forthcoming C6-R race car, but they boil down to the application of lessons that could only have been learned after countless laps of endurance racing-everything from suspension geometry to aerodynamics. What the engineers developed was a totally unique vehicle that has its own powertrain, body structure, and chassis system, which are distinct from other Corvette models.
"The new Z06 is the dividend from competing so successfully in endurance racing," said Dave Hill. "It combines the strong attributes of the new, sixth-generation Corvette with the spirit, technology, and know-how from the race program to form an American supercar with outstanding credentials."
The Z06 has a unique aluminum body structure for optimum stiffness and light weight for the fixed-roof body style. Perimeter rails are one-piece hydroformed members featuring cast suspension nodes, which replace many welded steel components on other Corvette models. Other castings, stampings, and extrusions are combined into the innovative structure with state-of-the-art manufacturing technologies. Advanced structural composites featuring carbon fiber are bonded to the aluminum structure. The wider front wheelhouses, for example, are carbon composites, and the passenger-compartment floors combine carbon-fiber skins with an ultra-lightweight balsa wood core.
The new Z06 achieves 500 hp in an approximately 3,130-pound (1,419.7 kg) package and is expected to deliver 0-60 performance of less than 4 seconds, eclipse the quarter-mile in less than 12 seconds, and deliver a top speed of more than 190 mph on a racetrack.
Primary Z06 components include:* LS7 7.0L, 427ci Gen IV V-8 with lightweight reciprocating components* 500 hp (373 kw) at 6,200 rpm* 475 lb-ft of torque (657 Nm) at 4,800 rpm* 7,000-rpm redline* Titanium connecting rods and intake valves* Dry-sump engine lubrication system* Engine handbuilt at GM's new Performance Build Center* Aluminum body structure with one piece hydroformed perimeter rails frame and magnesium front cradle* Fixed-roof design optimizes body rigidity and aerodynamics* Carbon-fiber composite front fenders and front wheelhouses * Unique front fascia incorporating a larger grille, cold-air scoop, and lower air splitter * Wide-body rear fenders and a unique rear spoiler incorporated with the CHMSL* Huge 14-inch (355mm) cross-drilled front disc brakes with six-piston calipers and 13.4-inch (340mm) cross-drilled rear rotors with four piston calipers*18x9.5-inch front wheels with 275/35ZR18 tires and 19x12-inch rear wheels with 325/30ZR19 tires* 3-inch-diameter exhaust with bi-mode mufflers and larger polished stainless steel tips* Engine, transmission, and differential oil coolers; steering cooler * Rear-mounted battery to improve weight distribution* Unique interior features, including revised gauge cluster and lightweight two-tone seats with more aggressive bolsters* Curb weight of 3,130 pounds (1,419.7kg), estimated* 3 inches (76.2 mm) wider than other Corvette models* Vehicle developed simultaneously with C6-R race car
The above features are merely the high points of the comprehensively designed Z06. Let's look a little closer at what could be considered by many the greatest Corvette ever built.
The New LS7 EngineThe all-new LS7 of the '06 Z06 reintroduces the 427ci engine to the Corvette lineup. Unlike the previous 427 engine, which was a big-block design, the new 7.0L LS7 is a small-block V-8, the largest-displacement small-block ever produced by GM and a tribute to its 50 years as a performance icon. With 500 hp and 475 lb-ft of torque, it is also the most powerful passenger-car engine ever produced by Chevrolet and GM. The LS7 is easily identified under the hood by red engine covers with black lettering.
The LS7 shares the same basic Gen IV V-8 architecture as the Corvette's 6.0L LS2, but the LS7 uses a different cylinder-block casting with pressed-in steel cylinder liners to accommodate the engine's wide, 104.8mm cylinder bores (the LS2 has 101.6mm bores). When compared to the LS2, the LS7 also has a different front cover, oil pan, exhaust manifolds, and cylinder heads.
Internally, the LS7's reciprocating components make use of racing-derived lightweight technology, including titanium connecting rods and intake valves, to help boost horsepower and rpm capability. The rpm fuel shutoff limit is 7,000 rpm.
The LS7's specifications include:*Unique cylinder block casting with large, 104.8mm bores and pressed-in cylinder liners*Forged-steel main bearing caps*Forged-steel crankshaft*Titanium connecting rods with 101.6mm stroke*Forged-aluminum flat-top pistons*11.0:1 compression*Dry-sump oiling system*Camshaft with .591-inch lift*Racing-derived CNC-ported aluminum cylinder heads with titanium intake valves and sodium-filled exhaust valves*Titanium pushrods and valvesprings*Low-restriction air-intake system*Hydroformed exhaust headers with unique "quad flow" collector flanges.
"In many ways, the LS7 is a racing engine in a street car," said Dave Muscaro, assistant chief engineer of small-block V-8 for passenger cars. "We've taken much of what we've learned over the years from the 7.0L C5-R racing program and instilled it here. There really has been nothing else like it offered in a GM production vehicle." All LS7 engines are assembled by hand at GM Powertrain's new Performance Build Center in Wixom, Michigan. The exacting standards to which they are built include deck-plate honing of the cylinders, a procedure normally associated with building racing engines and almost unheard of in a production-vehicle engine. Look for our LS7 engine story in this issue for all the down-and-dirty details on this killer engine.
Z06 DrivetrainThe Corvette Z06's powertrain and drivetrain systems are matched to the LS7's performance capability. The light, four-into-one headers discharge into new, close-coupled catalytic converters and through to new "bi-modal" mufflers. The mufflers feature a vacuum-actuated outlet valve, which controls exhaust noise during low-load operation but opens for maximum power.
At the rear of the LS7 engine, a single-mass flywheel and a lightweight, high-capacity clutch channel torque to the rear transaxle. The six-speed manual transmission has been strengthened to handle the LS7's increased torque load. The transmission includes a pump, which sends transmission fluid to the front radiator for cooling. Upon its return, the fluid removes additional heat from the differential lube before returning to the transmission. The M6 transmission connects to a limited-slip differential with enlarged ring-and-pinion gears. Stronger axle halfshafts with tougher universal joints transmit power to the rear wheels.
New Chassis SystemThe '06 Corvette Z06 has a new magnesium cradle that serves as the attachment point for the engine and some front suspension components. Magnesium is lighter than aluminum yet incredibly strong. This magnesium cradle helps improve the front-to-rear weight distribution, as do carbon-fiber front fenders and wheelhouses. Engineers also moved the battery from underhood to a position in the rear cargo area, behind one of the rear wheels. "This is an instance where the street car uses more advanced material than the race car," said Hill. "We're constrained by rules to run the steel frame in the race cars, but we stretched to bring even more performance technology to the street for our customers." The mass reductions are offset by some added performance enablers, including dry-sump lubrication, 3-inch (76.2mm) exhaust with outlet valves, larger wheels and tires, more powerful brakes, and stiffer roll stabilizers.
Suspension, Brakes, Wheels, And TiresThe Z06 retains the 106-inch (2,686mm) wheelbase of other Corvette models, as well as the short-long- arm suspension and transverse leaf spring design, but it rides on all-new wheels, tires, brakes, as well as its own rear spring and roll stabilizer.
The firmer suspension uses large 18x9.5-inch cast-spun aluminum wheels and 275/35ZR18 tires in the front, and 19x12-inch cast-spun aluminum wheels with 325/30ZR19 tires in the rear-the largest wheel-and-tire combination ever offered on a Corvette. The tires use the latest extended-mobility technology from Goodyear to provide a satisfactory ride, but still allow the vehicle to achieve lateral acceleration of more than 1 g. The extended-mobility tires eliminate the need and weight for a spare tire and jack or inflator kit, and reduce the chance of a sudden loss of handling capability.
Complementing the new suspension system and large tire/wheel combination is an equally capable four-wheel disc-brake system, consisting of 14-inch (355mm) vented and cross-drilled front rotors and 13.4-inch (340mm) vented and cross-drilled rear rotors. For comparison, the '05 Corvette has 12.8-inch (325mm) front and 12-inch (305mm) rear rotors, while the '05 Corvette with the Z51 has 13.4-inch (340mm) and 13-inch (330mm) rotors.
Huge, red-painted six-piston calipers that use six individual brake pads act upon the front rotors. Individual brake pads are used because they deliver more equalized wear compared to what would otherwise be a pair of long single-piece pads. For the rear brakes, four-piston calipers with four individual brake pads are used. There is a Delphi four-channel ABS system, as well as a competent active handling system, complete with a Competitive Driving mode. The large brakes should bring an excellent level of stopping capability with the Z06; and with their four-wheel brake cooling, they should provide excellent fade resistance and lining life during track duties.
Daily Driver AmenitiesFor all its race-inspired functionality, the Z06 is designed to be a daily driveable high-performance vehicle. To that end, comfort and convenience are held to a high standard. HID lighting, fog lamps, leather seating, dual-zone air conditioning, cabin air filtration, and Head-Up Display (HUD) with track mode and g-meter are all standard.
The Z06 also has a revised gauge cluster that displays the Z06 logo on the 7,000-redline tachometer, as well as a new readout on the oil-pressure gauge to reflect the higher standard pressure of the dry-sump oiling system. And, like other '06 Corvettes, the Z06 has a new, smaller-diameter three-spoke steering wheel that provides a more agile, performance-oriented feel. The seats feature two-tone leather surfaces, with Z06-logo embroidery and contrasting stitching.
Z06 options include a Bose audio system with an in-dash six-CD changer, polished wheels, a telescoping steering wheel, heated seats, side airbags, a navigation system with GPS, HomeLink, and XM satellite radio.
But for all its comfort, GM engineers did sacrifice a few components in the quest for lower weight and higher performance:* The seat side bolsters are fixed and more aggressive to better hold the driver when cornering, and they weigh less than standard-model seats.* The passenger seat features manual controls, saving the weight of a power-adjust motor.* The acoustic package was revised to reduce weight and allow more aural feedback of the powertrain.
Indeed, the new Z06 is the fastest, most powerful car ever offered by Chevrolet and General Motors. It looks to offer an unprecedented level of capability and technology, making it one of the greatest performance values on the market. And with an unmistakably muscular appearance, the '06 Z06 has a visual attitude that seems ready to demonstrate Corvette's winning attitude to any challenger around the globe. Production of the '06 Z06 will begin in the second half of 2005 at the Bowling Green, Kentucky, Assembly Plant. Now we just have to wait awhile before we get to drive this beast, and we can't wait.